Plate polishing machine



Jan. 4, 1944. ILLMER ETAL 2,338,644

PLATE POLI SHING MACHINE Filed De 30, 1940 s Sheets-Sheet 2 as 6- m2? S Q 27@ 7 n I Q S INVENTORS.

I I LOUIS ALMA VErP/va/v/F Faun:

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1944- L. ILLMIER EI'AL 1 PLATE POLI SHING MACHINE Filed Dec. 30, 1940 3 Sheets-Sheet 3 0 I02. I IOI I 65 9e INVENTORSI L o u s /L L MEI? VERNON A? Pa 4 as Patented Jan. 4 1944 ELATE POLISHING MACHINE Louis Illmer and Vernon R. Pallas, Cortland, N. Y. said Pallas assignor to Leota T. Pallas Application December 30, 1940, Serial No. 372,242

16 Claims.

The present invention broadly relates to the art of abrasive surface finishing equipment, and more especially pertains to an improved. nonrotating head type of machine which by the use of abrasive tapes, is adapted to intensively treat a fast moving cylindrical plate or a continuous sheet of strip stock. Our machine is particularly designed to efficiently pregrind and to polish high tensile stock such as annealed or hardened stainless steel without requiring any fast moving machine members except for the treated plate itself, said plate or strip being rapidly dragged and thereby abrasively stroked in a lengthwise direction.

It is herein preferred to resort to a succession of compact feed housings or headstock units, each serving to mount one or more abrasive tapes whose respective rectilinear cutting zones are laterally distributed crosswise over a localized region of a treated fiat surface. The abrasive action of each such zone may be maintained at a uniform rate and the tape grit substantially spent in one pass through such zone. The grit of each slowly advanced tape thereby becomes well loaded with abraded material prior to being allowed to issue tangentially from a particular zone.

As a result of final self -loading and wear, even fast cutting coarse tape such as 30 mesh grit, may by deterioration be made to take on an equivalent finer grit adapted to leave a treated plate surface with a relatively high degree of polish in which the scratch marks are hardly visible to the naked eye. Because of scale, the lack of rolled smoothness, pits and the like inherent surface defects, it is advisable to first rough or pregrind thin metallic plates to establish a truly flat superficial base that will lustrously polish. Thereupon any previous longitudinal scratch marks may be effectively and substantially removed by the use of fine grit tapes; the slower cutting property thereof effects an improved polish that may be kept free from any pronounced deep scratches when microscopically inspected.

W hen grinding a thinly rolled sheet of extreme width, it is expedient to work with multiple component tapes and cooperating sectionalized back shoes therefor that are respectively kept narrower than the overall plate width and disposed to collectively contact the plate crosswise of its path of travel. Such side by side tape and segmental shoe application facilitates a uniform and commercially complete utilization of all available grit. In order to obviate any gap between our oifset component tapes, certain contiguous longitudinal edges are given a slight overlapping registry to bring about a streakless finish over the entire treated plate width. Each separate tape of finite length is preferably supplied in roll or equivalent stripable form of vernation and regularly advanced into its localized cutting zone by continuously operated feed means.

The inherently limited abrasive capacity of finer tape grits is herein fortified by ample collective width on part of the numerous roll tapes employed. High tensile stock may be rapidly drawn therethrough for stepwise treatment and thus work toward a lustrous superficial finish. Our machine crowds a large number of such cooperating tapes in relatively small space without need of any endless abrasive belts, since the cutting action of such belts is not uniformly maintained but becomes proportionately sluggish by deterioration after their virgin grit has been partially spent.

A preferred plate traverse or travel velocity for our tape treatment lies in the neighborhood of several thousand feet per minute, which in turn affords a correspondingly ample productive capacity for a given collective width of manifold roll tapes and a corresponding low labor attendance cost. For a definite superficial material hardness, the tape cutting rate is in part fixed by the applied plate velocity and the tape backing pressure.

Provision has also been made for adequate tape storage capacity sufficient to supply their respective cutting zones for long continuous operation. The several roll tapes may be adjustably advanced at an exceedingly slow rate from a manipulative control to suit different requirements. In addition, our machine may be equipped with pneumatically controlled backing shoes or jaws that simultaneously thrust their respective tapes toward the treated plate. These jaws are preferably sectionalized and the segments made in-- dividually retractible and pressure regulated from a centralized point. All component tapes are positively and regularly advanced to provide for a continuously renewed abrasive zone and gross tape feed that may be accurately held to the minimum needs for different kinds of tape grit and plate material.

It may be emphasized that the instant grinder is of the socalled floating type in which the tape backing agency is yieldably retained. In the case of treating comparatively wide sheets of stock up to 60 inches, serious difiiculty is likely to be encountered in maintaining a substantially uniform backing thrust across the entire plate width.

When a backing roller of reasonable diameter is used, the flexure of a floating abrasive under lateral loading, generally exceeds the inherently small chip thickness or cutting depth per pass.

In the case of narrow, relatively thin strip stock, it is preferred to rapidly pass the same longitudinally through our polisher by the use of complementary drums or reels. For a comparatively wide but thicker plate, it is preferred to afiixedly curl such stock around alarge diameter rotor rim and then rapidly rotate the rim beneath manifold tape grinder units for abrasive or polishing treatment.

The object of our invention is to devise apparatus of the indicated character capable of effectively utilizing one or more floatingly mounted abrasives and to provide for a sectionalized backing agency of which each component is independently loaded to attain an equalized and evenly distributed cutting thrust along the collective length of said agency when applied to grinding a sheet face of comparatively wide marginal dimensions.

The present specification is descriptive of a machine analogous in certain respects to the teachings set forth in our copending application, Serial No. 366,596 as filed Nov. 22, 1940, now Patent No. 2,284,904, dated June 2, 1942.

Reference is had to the accompanying three sheets of drawings which are illustrative of alternative exemplifications of the instant invention, and in which drawings:

Fig. 1 schematically represents an elevational side view of our abrasive machine equipped with associated reels for treating strip stock.

Fig. 2 fragmentally shows a detailed side view of the machine proper to include a series of grinder units and their actuated tape feed mechanism.

Fig. 3 is an end view of the Fig. 2 assembly.

Fig. 4 shows a top view or" one such grinder unit, and Fig. 5 details a cross-sectional view taken along 55 of Fig. 4.

- Fig. 6 illustrates the cutting efifect of over- I lapping tape edges. 7 'Fig. 7 is similar to Fig. 5 but illustrates a modified type of tape backing jaw, and Fig. 8 shows a cross-sectional view taken along 8-8 of Fig. '7.

Fig. 9 details a top view of our strip tightener devices taken along 9-9 of Fig. 1.

Fig. 10 schematically indicates modified twin driven strip loops that are cooperatively arranged.

Fig. 11 represents an upright face view of another type of machine of which the rim is loosely embraced by a split yoke section having a series of staggered grinder units disposed radially therearound.

Fig. 12 shows a cross-sectional view taken along l2-l2 of Fig. 11, and Fig. 13 details a plate cleat block taken along I3-l3 of Fig. 12.

Referring more specifically to the Figs. 1 to 6 disclosures, one type of our machine may comprise a skeletonized horizontal framework including a bed plate it! having a hardened face plate or stationary platen l I superimposed thereon, it being understood that all such parts including the understructure props I2, are to be welded or otherwise rigidly secured together. For reasons that will appear presently, the opposed longitudinal side beams such as I5 of said base may be bridged by mated cross rails [3 that may respectively be located beneath the several transverse tape cutting zones (see Fig. 5). In

1y small reelable plate thicknes less than the A long' length of such fiat stock may have its ends slotted gap dimension T (see Fig. 3).

smoothly butt welded into an endless band and carried into belted engagement with the axially A belt tightener pref-- spaced drums H and I8. erably comprising a plurality of narrow weighted rollers 20, are independently linked at 2! and distributed across the strip width to tension the In lieu of an end-- less belt, the respective free strip ends may also be wound about said drums in reel fashion and same for proper drum grip.

rotated to bring about successive strip passes in reverse travel directions. However the use of the contemplated endless strip materially simplifies the motorized reeling equipment and eliminates the time loss required to reverse the direction of high speed strip movement during successive:

passes. The drum diameters are preferably of a sufiicient size not to kinkingly flex the strip stock beyond its elastic limit.

Spanning the respective side beams, are a series of independently demountable grinder headstocks such as 23. These duplicated tandem units may respectively comprise a pair of channelled side bars 24 and 25 that are fixedly interconnected by mated cross bars 26 and 21 to constitute a skeletonized superstructure. Each such framework may be separately secured in place by the tie bolts 29 or the like detachable clamping agency. A spaced block 30 may underlie mated side bars to provide for a slotted plate receiving gap having a width W.

Fixedly erected upon the respective spaced side bars of each headstock'are the laterally braced spool brackets 3| and 32. A pair of parallel spool spindles 33 and 34 demountably span said brackets and respectively carry thereon a component supply of abrasive roll tape of finite length such as 35 or 36 whose paper backed grit is faced radially outward. As will appear from Fig. 3, the axial length of the respective tape spools on each axle is purposely kept shorter than the plate width W and in a substantially aliquot relation thereto. The demountable spool flanges may be kept laterally spaced by the interposed bushings 31. All tape carrier spools on one spindle are preferably staggered with respect to the spools on a mated spindle to provide for a slight flange overlap marked L. The virtually telescoped next adjacent tape edges may thereby be retained against separation and thus uniformly grind over the entire width of a truly flat treated plate without disconnection or final intervening ridges. It will be obvious that instead of spiral convoluticnsQthe same result may be had with tapes of finite length when fed from other forms of vernation.

In order to obviate longitudinal edge interference while independently and slowly advancing the corresponding outer ends of the several component tapes such as 35 and 36, the respective tape supply carriers may be kept laterally spaced and offset in the manner indicated in Fig. 2, said tapes being directed to separate parallel cutting zones respectively extending crosswise of the strip stock. To this end, the apertured webs of the side bars 24 and 25 may journal twin sets of rollers therebetween as depicted in Fig. 5.

The duplicated rollers or the like tape guide means 33 and 38' are laterally spaced from their respective positively actuated .feed rollers 39 and 39'. interposed between each pair of mated rollers '33 and 39, is a plurality of elongated tape backing jaws or relatively stiff metallic shoes fill or 6d of comparatively short length disposed in tandem lengthwise of the cross bars 25 and 2? and which shoes may respectively have a circular tape contacting profile denoted by the radius R. As will appear in dotted outline from Fig. l, the .several shoe ends are overlappingly staggered to respectively correspond with the offset component tapes 3t and To prevent excessive ed gewise shift on part of the fed tapes, their respective feed rollers may be perimetrical-ly as at 4 l.

Each virgin tape component is threaded around its guide roller and beneath an associated shoe into abrasive contact with the treated plate iii as shown, whence the spent tape is gripped about its driven feed roller. A guard vane 5d may be spacedly installed between the shoe t ll and its feed roller to prevent lateral buckling of the fed tape. A swingably suspended idler roller d2 may be spring equipped to urge the spent tape in. n in slipcontact with its feed roller. Cori'esp idler rollers are preferably carried by a common bridge strap whose ends may be secured to overhanging foot flanges such as M inset from the base of the respective spool brackets 35 and 32.

A similar parallel head strap 4E5 may be employed to mount a plurality of depending bored guideways such as Slidably entered into each such bore is a. hollow retractible plunger 5-! of which the lower en is provided with a pintle arranged to medially pivot a shoe thereon. A metallic bellows or the like sealed diaphragm means #23 may be operatively inserted within each plunger to independently thrust its backing shoe toward the treated strip surface. An'air lead pipe :28 may nterconnect the grouped bellows to a cannon fluid supply header 52. Each branch c may be placed up r the control of a corned back pressure to regulate the prev ng shoe thrust and constitute a self-compensation shoe agency. An auxiliary tension spring 52 (see Fig. 5) may serve to retract its shoe and fully release the tape backing pressure when said lead pipe is vented. Our several independently actuated shoe agencies when loaded simultaneously bring all of their respective component tapes into intensive operative engagement with on ion treated surface, it being pointed out that said plural agencies collectively maintain a substantially equalized tape backing pressure distributed across the entire surface width although the head strap 45 may suffer considerable lateral flexure in opposing the reacting shoe thrust. If desired, a knife edge 53 may bridge the bracket foot flange to occasionally sever the surplus spent tape.

Because of the combined downward thrust exerted behind the numerous backing tapes, it is desirable to alleviate the resulting frictional drag between the stationary platen I I and its slidably superimposed strip stock I6. To this end, an interposed wear hoop 22 of relatively thin bronze sheet metal or the like readily replaceable carrier may be loosely belted about the uplift rollers 14 and M in the manner indicated in Fig. 5. Such anti-friction carrier means may be slipp-ingly dragged along by the fast moving strip stock l6. Suitable lubricant may be applied to the inner vent cock 5i whereby hoop side face and conveyed onto said upturned platen face to protect the latter against excessive drag Wear. The cited high velocity or rate of longitudinal advance permissible in our machine, promotes a fast tape cutting rate and without sacrifice in performance, allows of reducing the shoe pressure to moderate intensity as compared with the use of a higher tape backing pressure operating on a plate dragged at a relatively slow velocity.

Referring now to the mode for positively actuating the tape feed rollers 39 and 39, the respective ends thereof may be journaled to project through the web of the side bars 2d and and have a similar spur gear 55 or 525 affixed to corresponding feed roller ends (see Fig. 4) Loosely carried around a projecting end of the interposed guide roller 38, is a meshing intermediate spur gear 57 to which the worm gear 58 may be fixedly secured. As shown in Fig. 2, a lay shaft 59 may be bracketed to one of the side beams l5 and provided with a plurality of worms such as iii] which respectively engage the gear 58 of the several headstock units for unitary feed roller movement. A sprocket 6| and endless chain 62 may be driven by the motorized variable speed transmission unit $3 of a conventional type provided with a centralized finger tip control 64 whereby to manipulatively alter the tape advance within wide feed limits without having to interrupt the travel of the dragged flat stock.

Figs. 7 and 8 reveal an alternative style of tape backing jaw but in other respects remain sub.- stantially identical in function. with the previously described instrumentalities. Here a. closedended, tubular rubber backing shoe or the like resilient plastic agency 65 ma be suspended from a relatively stiff bridge header strap 66, as shown. The initial cross-sectional shape of this relatively thin sho backing agenc is preferably moulded or extruded into a relatively flattened elliptical profile 55 indicated in dotted outline. Opposed end regions of the minor axis of such profile may be equipped with reversely wedge shaped longitudinal lugs 67 and One such reenforcing lug may be tightly gripped between the cleats 69 and firmly suspended from said cross strap as shown. The other rounded lug face may be armoured by an insulated metallic shoe sheath 1i! and electrically wired at H to a warning signal or the like relay. Inadvertent rupture on part of an interposed tape such as would ultimately allow said shoe sheath to come into direct electrical contact with the treated metallic stripstock l6 and thereby close the circuit through the wire ll to warn the operator of defective tape feed. It will be apparent that the pivoted shoe 4!! of l may be likewise equipped when electrically insulated from adjacent metallic parts.

The ends of the tubular shoe backing agency maybe sealed in any suitable manner, preferably by inserted relatively resilient end plug or rubber caps such as l2. The tube interior may be fed by a branch p l, supplying regulated low pressure air or the like inflation medium thereto. Being rigidly reenforced by a laterally stiif header strip fill, our resilient backing shoe may be kept to component tandem lengths or one substantially equal to the p ate width W and still maintain compensated contact across the whole of a treated flat face. A moderate llifis tion pressure within the initial tube profile is sufficient to cause such closed rubber shape to more nearly assume a circular contour which in turn imposes a regulatable shoe thrust that is kept evenly distributed across the entire width of the treated plate it. Although no wear loop 22 (see Fig. 5) is shown associated with the rubber backed shoe 78, its use might likewise prove It is preferred to work with staggered multiple tapes in the Fig. 3 manner. Fig. 6 schematically clarifies in exaggerated scale, the eifect of the cited overlapping tape edges. Assuming the first engaged pair of spaced abrasive tapes 35 and 35' to have superficiall ground away the plate IE to a shallow cut depth designated 1 and leaving a slight ridge l5 therebetween. then the trailing tape 36 will follow up such depressed level with an approximately identical out. It will be observed that in the respective overlapping edge regions (marked .L), the interposed tape 36 would not begin to abrade such regions until this newly established depressed face has been reached, thus bringing the treated plate face into a ridgeless condition.

Referring further to Fig. '7, this reveals a novel mode of abrasive treatment practiced herein. The virgin tape 35 as it comes from its spool may be regularly and positively advanced by the feed roller 39 toward the substantially fiat cutting zone 13 having a relatively narrow eiiective contact width marked Z. By spreading apart the centers of the shoe curvature radii as shown and medially interconnecting the arcuate shoe profile ends or lips by a chordwise component, such resiliently backed contact may be made to enlarge the abrasive capacity of each tape.

Upon approaching the slightly divergent edge of such zone, the tape is still virgin but the shoe thrust is preferably maintained at a sufiicient magnitude to substantially reduce the initial abrasive property of the tape by the time it slowly emerges from the convergent end of such zone. The requisite shoe pressure needs to be nicely adjusted in accordance with the tape grit and the character of material treated, since eX- cessive shoe pressure may tear or burn its underlying tape. The resulting stock removal is also dependent upon the'ra-te of tape advance and the grit mesh.

When the flat metallic strip i6 is dragged rapidly in the direction of the tape advance as in Fig. '7, the last treated strip surface tangentially issues from the localized cutting zone 73 in a region where its grit is partially filled or deteriorated by wear. The final substantially spent condition of the abrasive tape 35 imparts a virtual burnished finish to the treated stock by accumulative grit loading. In order not to drag and crowd along the tape faster than the desired advance rate fixed by the adjusted feed roller 39, a suitable braking action may be exerted upon the tape supply. Such effect may in part be brought about by obstructing rotation of the guide roller 38 to keep the tape taut. The guard vane 54 prevents buckling should any unwanted tape slackening occur.

In order to renew the supply of roll tape or change the grit thereof, each headstock unit 23 may be independently demounted by removing the clamping bolts 29, whereupon a new free tape end may be conveniently threaded in place for re-installation upon the bed plate It). Should it be desired to first coarse grind and then polish with finer tape, spare headstock units respectively provided with appropriate grit, may be interchangeably substituted on a common bed plate.

The length of spent tape may occasionally be torn off by the use of a cutter 53 or the like without requiring any tape take-up bobbins. The bracketed tape spools are kept sufficiently spaced to afiord convenient access to the spent tape and said knife edge 53. The compact Fig. 2 or the like assembly affords scant room into which to install any tape take-up spools without serious encroachment upon such accessibility. While only two tailstock assemblies are shown erected upon the bed plate It, these may be multiplied to any desired extent, it being preferred to employ sufficient units to allow or rapidly pregrinding or polishing the reeled strip stock without requiring an excessive number of passes through our machine.

The manipulative control 64 of the speed transmission unit 63 is to be selectively set to a proper feed for regularly advancing the respective tapes into their cutting zones. Our abrasive tape may either bed fed with or counterwise to the direction of plate travel by the roller feed mechanism shown in Figs. 5 or '7. For a given performance, the total tape needs remain substantially constant irrespective of the number of headstocks employed. In lieu of fine abrasive tapes, a fabric buffing strip may be substituted to further enhance the final polish. In either case, our machine provides for abundant collective tape contacting area arranged to successively treat a flat plate on a relatively rapid multi-stage processing basis capable of attaining a high degree of superficial luster at low labor cost. The tearing or other faulty behavior of a single component roll tape does not seriously interfere with or reduce the combined performance of any large number of remaining tapes. The electrical telltale means 1| promptly signals the operator should any one tape become severed. The air pressure carried in the header 53 is to be held to a limit that will prohibit any excessive shoe backing thrust.

As regards treatment of narrow strips having a width considerably less than the gap dimension W, this is exemplified in Fig. 9. The driven reels or belted'drums l1 and 3 may respectively be provided with an axially shiftable collar 1'! which slips adjustably relative to a flanged drum end to alter the guided belt width. One or more narrow strips of endless stock such as IGA and IE3 may then be interposed alongside each other to lie in a common plane as shown. A separate linked roller 20 may be employed to tension each strip independently when belted in registry beneath a single outer tape such as 36 of Fig. 3. In such instance, the feed rollers associated with the remaining tapes carried by the spool spindles 33 and 34 may be made inoperative and thus adopt a common machine to advantageously handle both multiple narrow strips or a single wide strip.

As a further modification, attention is directed to the duplex belt layout of Fig. 10 in which corresponding mated parts are respectively identified by the letters A and B appended to the reference numeral previously used. Here a pair of endless bands of metallic strip stock are respectively mounted between the driven drums llAll'B and l8A-I8B to provide for alignedly superimposed beltlike components or spanning sections 15A and "SB that may be motor driven at the same linear velocity in a common direction without substantial slip therebetween.

A separate belt tightener weight 29A and 25B may serve to independently tension each of the superimposed metallic belt sections. Directly opposed or dual tape backing shoe means 40A and 40B may respectively be installed to thrust such superimposed strip sections toward each other in balanced relationship. As will be understood, said shoe means are respectively to be equipped with suitable tape means and with feed means that may be kept similar to Fig. except that the wear hoop 22 is eliminated since the stationary platen II is no longer required for the fully balanced shoe thrust assembly represented in Fig. 10. In order to obviate marring the fine finish obtained along our treated inner strip faces, the several metal drums may each be sheathed with chamois leather or the like soft protective agency. When abrading a relatively wide strip, the mated dual shoes 48A and ltB may be given a staggered endwise shift with respect to the shoes 48A and NE in the Fig. 4

manner.

An alternative machine embodying substanti. lly the same underlying processing features, is disclosed in Figs. 11 to 18. In this instance a relatively wide metallic plate 59 of non-reelable stock is adapted to be treated by snugly curling such relatively thick sheet as a cover sheath or band about a suitably sized cylindrical rim 8%. Such rotor rim may be provided with one or more cross grooves 81 adapted to reversely cleat opposed transverse plate edges in the abutting Fig. 13 fashion. Said sheet may be drawn into tight embrace with the rim perimeter by the use of supplementary clamp straps (not shown) and then have the transverse sheet edges inturned against the groove side walls to again constitute a substantially endless band for abrasive treatment. An interposed flush wedge block or screw retained cleat 2 spans the groove gap and may grip such inturned edges to smoothly secure the plate ends in place when the rim shaft or axle 83 is rapidly rotated between a pair of pedestals 84 by a belt driven pulley 85. The pedestal caps are split to facilitate rim removal. Rotation of the rim imparts the desired high rate of velocity to the plate is for roll tape abrasion when cooperatively dragged past one or more inbuilt headstocks.

An arcuate yoke or the like framework assembly preferably comprises a pair of laterally spaced semi-circular channel girders 8% and M of which their respective ends may be propped upon the mated standards 88 and 89, One or more laterally corrugated T irons such as 90 may be alignedly interposed between said channel girders and rigidly cross braced by suitable struts, also by the complementary shoe sustaining header straps 9| and 9| to constitute a rigid unitary structure that is kept freely spaced from the cleated plate in a concentric relation to the rim shaft 83. One such yoke end may be hingeclly connected at 92 to its standard 88 and the other channel end releasably clamped at 98 to a mated standard 89 whereby said unitary framework may be bodily swung about its pintle 92 into and through the raised yoke position indicated in dotted outline by Fig. 11. w

Radially distributed around the outer perimeter of said framework are two series of roll tapes such as 93A to 93D and 94A to MD. Alternate tape supply spools may be carried between the offset brackets 95 and 95' and it and 96' whose mounting spindles 91 and 91 may respectively span a different outer channel and the interposed iron 90, as shown. The plurality of complementary shoe sustaining straps 9| and 9 l may likewise bridge such ring shaped members ina coordinated relation to their respective spool spindles and may have individually affixed thereto, the rubberized tape backing shoes 99 and 99 in a manner corresponding to the Fig. '7 layout or the like. The accompanying relatively long mated rollers may be disposed between next ad-- jacent arcuate girders and journaled therein.

Each outer feed roller end may be positively actuated by an overhanging worm gear E89 that respectively mesh with the articulated worm shafts illl having a universal coupling Hi2 between the several sections thereof. One coupled shaft end may be slip connected into the sleeve ass that be rotated by the bevel gears I04 and variably driven by the same type of speed transmission 63 used in Fig. 2.

The feed shaft drive connection is such as to permit the assembled yoke to be unrestrictedly lifted clear of the drum rim Bil. A new sheet may be installed for treatment by dislodging the wedge cleat 82; in a two-stage stepwise grinding operation said drum together with its cleated sheet may after pregrinding, be bodily removed from its pedestal into another similar machine assembly whose yoke is provided with finer polishing tapes. It is the intent to continue rotating the virtually endless sheet in one direction at high velocity until the perimetrically distributed cutting zones of several component tapes have conjointly abraded or polished said sheet to a desired extent. Because of the adequate tape contacting area afforded by such multiple tapes and the considerable air cooling effect provided by our high speed rotor, the abrasive treatment may be carried out at a correspondingly rapid rate and thus also provide for a comparatively large productive capacity for our machine of the drum type. After completion, the removed sheet 19 may be straightened into a perfectly flat condition. If desired, the backing shoes and feed roll mechanism may be equipped with the same auxiliary control devices that have been more explicitly defined in connection with the drum type of machine. In either headstock type, the tape may be utilized in a dry or in a lubricated state.

The foregoing disclosure will, it is believed, make evident to those skilled in this art, the outstanding commercial advantages which our grinder improvements afford over the prior art. It is further emphasized that certain aspects of the tape housing assemblies are likely to find application to purposes other than the superficial abrading of metallic sheet stock and that we reserve the'right to correspondingly modify oertain disclosed structural features of our illustra tive embodiments, all without departing from the spirit and scope of our invention heretofore described and more particularly characterized in the appended claims. I

-We claim:

1. In a machine for polishing plate stock with abrasive tape and imparting a virtually burnished finish thereto, an elongated framework arranged to transversely mount a succession of actuated feed roller means having their respective axes laterally spaced lengthwise of said framework and which. roller means are all disposed in substantial parallelism along on side face of the treated stock, each such means being supplied with a 00- operating abrasive tape whose width is kept narrower than the overall width dimension of said one side face and which component tapes are parallelly offset in staggered relationto collectively establish a combined cutting zone extending continuously across said overall width dimension and.

collectively disposed to treat the entire width of said one side face, multiple independently actuated shoe means respectively imposing a distributed backing thrust behind each such tape component, header strap means tran versely bridging said treated face in opposition to certain of said shoe backing thrusts and which respective shoe means individually maintain their associated tapes under a substantially equalized backing thrust, and means for stroking said treated face in a direction crosswise of said combined zone at a certain rate of traverse, certain next adjacent longitudinal tape edges being disposed in overlapping registry to obviate leaving an intervening ridge in the finished face and which rollers feed their respective tapes into said combined zone at a rate of advance materially slower than the aforesaid rate of traverse.

2. In a machine for treating plate stock with abrasive tape, an elongated framework arranged to transversely mount a succession of actuated feed roller means having their respective axes laterally spaced lengthwise of said framework and which roller means are all disposed along one side face of the treated stock, each such means being supplied with a cooperating abrasive tape of finite length in strippable form of vernation and the width of which tape is kept narrower than the overall width dimension of said treated face with corresponding end regions of the respective tapes parallelly arranged in staggered relation to collectively span a major portion of said overall width dimension whereby to establish plural substantially parallel abrasive zones extending crosswise along and in operative engagement with said one treated side face and having overlapping zone ends to constitute a combined cutting zone, multiple independently actuated shoe means respectively imposing a distributed backing thrust behind certain of such tapes, header strap means transversely bridging said certain tapes in opposition to the shoe backing thrust imposed thereon and which respective shoe means individually maintain their associated tapes under substantially equalized backing thrust, and means for stroking the plate stock in a direction crosswise to said combined zone.

3. In a machine for treating sheet stock with abrasive tape, a stationary framework comprising similar substantially semi-circular yoke members that are spaced apart and laterally braced to constitute a unitary yoke structure having depending ends, mated standards demountably upholding the respective yoke ends, a pair of pedestals located between said standards and which pedestals demountably uphold an axle in a coincident relation to the curvature center of said yoke members, endless rim means rotatably carried upon said axle and loosely embraced by the yoke members and which rim means is arranged to have a sheath of sheet stock afiixedly curled about the perimeter thereof beneath the yoke members at a uniform radial distance from said center, a series of actuated feed roller means spanning the yoke members for lengthwise distribution therealong and which roller means are respectively supplied with a cooperating abrasive tape that are respectively impressed radially inward into operative engagement with the curled sheet to constitute a succession of cutting zones, and drive means for rotating such zone embraced rim means, said yoke when demounted permitting the sheathed rim to be bodily withdrawn upwardly.

a. In a machine for treating fiat stock with laterally pliant abrasive tape, faced platen means, a skelentonized headstock assembly demountably erected upon the platen face and arranged to provide for a stock receiving gap slot therebetween, said assembly comprising opposed side bars and interconnecting cross bars which lat ter span said slot, an actuated feed roller whose respective ends are journaled in said side bars, an elongated backing shoe cooperatively disposed alongside the feed roller, the length of said shoe being kept materially shorter than the stock width and subjected to a substantially uniform backing thrust distributed along the entire shoe length, drive means slidably dragging entered flat stock along the platen face through said slot and beneath said shoe, a supply of abrasive tape carried by the headstock and which tape is operatively threaded between the shoe and said flat stock and extended onward into gripping engagement with the feed roller, a meshed worm gear mounted to drive a journaled feed roller end, and a variable speed transmission unit arranged to worm drive said gear, the demountable headstock assembly being separable from said worm drive.

5. In a machine for treating flat stock with laterally pliant abrasive tape, platen means having an elongated face, a series of headstocks respectively arranged to span the longitudinal edge regions of said face to constitute a succession of registering stock receiving gap slots, drive means slidably dragging entered flat stock lengthwise through said slots, multiple roll tapes bracketed upon each such headstock and corresponding ends of which tapes are respectively brought into abrasive engagement with the flat stock, said tapes being kept narrower than the overall width dimension of the fiat stock and disposed in staggered edgewise relation, a backing shoe and a feed roller cooperating with each such corresponding tape end, the length of said shoe being kept materially shorter than the stock width and subjected to a substantially uniform backing thrust distributed along said shoe length, a worm gear arranged to simultaneously rotate the respective feed rollers comprised in each head stock, and a driven lay shaft extending length wise of the platen and provided with plural worms adapted to actuate the several worm gears inunison.

6. In a machine for treating flat stock with laterally pliant abrasive tape, means, a skeletonized headstock assembly erected upon the platen face and arranged to provide for a stock receiving gap slot therebetween, said assembly comprising opposed side bars and interconnecting cross bars which latter span said slot, an actuated feed roller whose respective ends are journalecl in said side bars, an elongated backing shoe cooperatively disposed alongside said feed roller, drive means slidably dragging entered fiat stock along the platen face through said slot and beneath said shoe, a supply of abrasive tape carried by the headstock and which tapeis operatively threaded between the backing shoe and the treated flat stock to constitute an elongated cutting zone and which tape is extended onward into gripping engagement withsaid feed roller, header strap means spanning the opposed side bars, and adjustable thrust means interposed between said strap means and theibackin shoe, said thrust means being self-compensating and adapted to exert a distributed substantially uniform thrust alongthe entire length of the out faced platen ting zone irrespective of lateral flexure on part of the header strap means.

7. A machine for treating endless strip stock with abrasive tape, faced platen means having unitary headstock means erected thereon and arranged to provide for a strip receiving gap therebetween, said headstock comprising opposed side bars and interconnecting cross bars, a pair of laterally spaced actuated feed rollers having their respective ends journaled in said side bars, each such roller being provided with axpair of mated tape centering flanges and which flange pairs are overlappingly staggered as measured lengthwise along their respective feed rollers, a separate elongated backing shoe cooperatively disposed along each such feed roller, drive means slidably dragging entered strip stock between the platen and the respective shoes, a dual supply of abrasive tapes that are respectively interposed between the strip stock and one of such shoes and carried into gripping embrace with its cooperating feed roller between the mated flanges thereof, complementary header straps bridging the opposed side bars in spaced alignment with the respective tape backing shoes, and remotely controlled thrust means interposed between each such header strap and the shoe aligning there.- with, said means serving to subject the several associated shoes to a distributed substantially uniform thrust along each of the respective shoe lengths.

8. A machine for abrasively treating fiat stock having mated side faces and which machine is provided with tubular tape backing shoe means of hollow elastic material having an elliptical profile, opposite perimetric regions of the minor profile axis being respectively reenforced by 1ongitudinal lug means of which one such is retained against flexure by header means, a supply of laterally pliant abrasive tape that is advanced crosswise of the shoe length in slidable cooperation with the other lug means to constitute an elongated cutting zone, said other lug means being arranged to impose a tape backing thrust di ected outwardly away from said header means an serving to maintain a substantially uniform thrust distributed along the entire length of said zone, drive means dragging a sideface of the treated flat stock into abrasive engagement with such backed tape, and sustaining means supporting the mated stock side face in opposition to said backing thrust.

9. A machine for abrasively treating fiat stock having mated side faces and which machine is provided with an hermetically closed inflatable shoe of resilient material comprising a tubular length of non-circular profile of which aperimetric region lying contiguous to one end of its minor axis is reenforced by header means, a supplyof laterally pliant abrasive tape that is advanced crosswise of the shoe length and arranged to slidably cooperate with the perimetric region lying contiguous to the opposite end of said minor axis to constitute an elongated cutting zone, said shoe serving as a tape backing agency that when inflated automaticall compensates for flexure on part of the header means and automatically serves to maintain a substantially uniform backing thrust distributed along the entire length of said zone, drive means dragging a side face of the treated fiat stock into abrasive engagement with such backed tape, sustaining means supporting the mated stock side face, and conduit means conveying inflating fluid into the shoe interior to distort the aforesaid 75 profile and thereby impose a shoe thrust upon the backed tape in a direction outwardly away from the header means.

10'. A machine for abrasively treating plate stock having mated side faces with opposed lon-- gitudinal edges and which machine is provided with a tape backing non-rotatable lug that is faced by a sheet metal shoe whose cross-sectional profile has an arcuate entrance lip and an adjoining chordwise component to constitute a narrow slightly inclined flat face portion extending lengthwise of said shoe in a perpendicular direction to said opposed edges, a supply of abrasive tape slidably cooperating with the aforesaid shoe face portion to establish a converging abrasive zone thereunder, actuated feed roller means slowly advancing the tape crosswise through said zone, drive means dragging one side face of the treated stock onward in the direction of tape advance at a relatively fast traverse with respect to the rate of tape advance and into initial operative engagement with the divergent region of said zone, sustaining means supporting the mated stock side face, and means imposing a thrust upon the flat shoe face portion,

said tape being substantiaily spent in one pass through its cutting zone whereby by grit attrition and accumulative localized loading to virtually burnish the plate stock in the convergent I region of said zone.

11. In an abrasive machine for treating flat stock, frame means equipped with grinder head means and providing for mated cutting zones component ends of one such shoe overlappingly staggered with respect to those in the other zone to uninterruptedl extend crosswise of the stock width, cylindrical rotor rim means including a supporting axle located in substantial coin cidence with the center of curvature of the aforesaid arc, said rim means being adapted to have flat stock afiixedly curled about the perimeter thereof, abrasive tape embracingly disposed to treat the enter alized shoes, header strap means associated with the respective cutting zones superimposed radially beyond said exterior face, individual pressure applying means interposed between the strap means and each separate shoe component serving to independently impress the latter radially inward and thereby maintain a substantially equalized cutting thrust upon all the components comprised in any one such sectionalized backing shoe irrespective of the overall length thereof, and drive means unidirectionally rotating said rim.

12. In an abrasive machine for treating sheet stock, a stationary frame structure comprising a plurality'of similar arcuate girders respectively spaced laterally to a distance materially narrower than the overall stock width, actuated feed roller means mounted between each pair of next adjacent girders in successive endwise relationship, spool spindles bracketed radially outward from each of the several girders and which spindles respectively mount a supply of abrasive roll tape having a marginal width less than its contiguous girder spacing and of which tapes corresponding ends are cooperatively carried to the feed roller thereof, cylindrical rotor rim means centered to revolve interiorly of an arcuate girder, said or stock face and which means are combinedly backed by said sectionmeans being adapted to have a sheet stock af-' fixedly curled about the rim perimeter, sectionalized backing shoe means of which a component is interposed between each such pair of girders and serving to individually impress its associated tape into abrasive engagement with the exterior sheet face, header strap means serving the respective backing shoe components, individual pressure applying means interposed between the strap means and each shoe component to independently impress its associated tape radially inward toward the rotor axis and thereby maintain a substantially equalized cutting thrust upon each of such several components irrespective of the overall sectionalized shoe length, and drive means for actuating the feed rollers in unison.

13. In an abrasive machine for treating sheet stock of substantial width, multiple sectionalized presser agencies each comprising a plurality of comparatively short components distributed tandemwise in a transverse relation to the opposed side edges of one stock face and which agencies are laterally spaced from each other to lie in an arc, a supply of abrasive tape means operatively interposed between the several presser sections of each such agenc and said face to combinedly establish a virtually continuous cutting zone extending crosswise of said face, means maintaining a substantially equalized tape backing thrust upon each of the respective presser sections comprised in each such zone, and means feeding the tape means onward into the zone thereof at a relativel slow rate of advance while said one face is being passed longitudinally at a velocity materially faster than the rate of tape advance.

14. In an abrasive machine for treating a length of fiat stock having opposed ends, said machine comprising driven cylindrical rotor rim means adapted to have said stock wrapped about the rim perimeter and which perimeter is transversely recessed, cleat means entered into said recess and serving to affix the respective stock ends, a sectionalized presser agency comprising a plurality of comparatively short components distributed tandemwise in a transverse relation to the exterior face of said wrapped stock, a supply of abrasive tape of which one region is operatively interposed between the respective presser sections and said face to establish a com bined cutting z'one, means maintaining a sub-' stantially equalized backing thrust upon each of the respective presser sections, means feeding the tape means onward into said zone at a relatively slow rate of advance, and drive means for rotating the rim means to progressively reduce the initial thickness of said sheet stock.

15. In a surfacing apparatus provided with means for mounting a longitudinally movable work piece of fiat sheet stock, a plurality of comparatively short presser units each confined to a length less than the spacing between the stock width margins and respectively having ends that extend in end to end relation crosswise to the direction of stock movement, a plurality of abrasive tapes operatively interposed between a side face of said stock and respectivel backed by one of the presser units, header strap means superimposed over said side face, and separate pressure applying means yieldably interposed between each such unit and said strap means serving to independently impress a corresponding abrasive tape into operative engagement with said side face and thereby maintain a substantially equalized cutting thrust upon each of the several presser units throughout the overall length thereof regardless of lateral flexure on part of the strap means.

16. In a surfacing apparatus provided with frame means for mounting a longitudinally movable work piece of flat sheet stock, duplicate rows of comparatively short presser units of which the respective units comprised in one such row extend endwise across said width in overlappingly staggered end to end relation to successive units in the other row to constitute a combined overall cutting zone length, abrasive means operatively interposed between a side face of said stock and backed by the respective units, header strap means superimposed over said side face, and individual pressure applying means separately interposed between each such unit and said strap means serving to independently impress a corresponding portion of the abrasive means into operative engagement with said side face and thereby maintain a substantially equalized cutting thrust upon each of the several presser units through out said zone length.

LOUIS ILLMER. VERNON R. PALLAS. 

